This is to support to Indian Health Services'Native American Res Centers for Health Study I Alaska/nicotine exposure and metabolism. Researchers at the Alaska Native Tribal Health Consortium (ANTHC) currently have funding for a Native American Research Center for Health (NARCH), through a joint program by the Indian Health Service (IHS) and the NIH. One of the projects proposed under the NARCH grant is titled "Nicotine Exposure and Metabolism in Alaska Natives." The primary objectives of this study are to 1) describe exposure to nicotine and carcinogens in Alaska Native adults who smoke cigarettes, use commercial chew tobacco, or use a homemade mixture of chew tobacco and ash (Iq'mik);2) characterize nicotine metabolism in Alaska Native adult tobacco users by measuring plasma 3'-hydroxycotinine:cotinine ratio and by genotyping genes related to nicotine metabolism;and 3) quantify the pH, free nicotine content, and carcinogen (tobacco-specific nitrosamine or TSNA) content in commercial chew and Iq'mik.